The present invention relates to a semiconductor device and particularly, to a semiconductor device that comprises a fuse for storing a data signal by being melted or not.
In a semiconductor integrated circuit device (semiconductor device), a fuse program circuit is used for various applications. In the fuse program circuit, the state of an output signal is set fixedly depending on whether a fuse element is melted or not. For example, in order to fine-adjust (trim) the constant of an analog circuit, such a fuse element is used. Specifically, programming (melt/not melt) of a fuse element is performed for the adjustment of the current drive force of a transistor element, the adjustment of the amount of supply current of a reference current source, and/or the adjustment of a reference voltage level generated by a reference voltage source. Further, in order to fine-adjust the resistance value of a resistor element, such a fuse program circuit is used.
Furthermore, in a semiconductor memory, it is necessary to program a defective address to identify a defective cell in order to replace the defective cell with a redundant cell and a fuse program circuit is used to store such a defective address. By utilizing such a fuse program circuit, the optimization of the circuit operation characteristics is realized whether the circuit is analog or digital and the improvement of yields is aimed at by restoring a defective cell in a semiconductor memory.
A configuration of a fuse program circuit including a wire fusing type electric fuse element that melts a fuse element with an electric current in such a fuse program is described in Patent Document 1 (Japanese Patent Laid-Open No. 2007-317882). In the configuration described in Patent Document 1, a fuse is formed using a wire in the upper layer of a multilayer metal wiring layer and a diffusion protective wall is formed so as to surround the fuse. The fuse is formed by a copper (Cu) wire and the cutting defect due to the diffusion of copper after melting is suppressed from occurring by the diffusion protective wall.